package main

import (
    "encoding/json"
    "fmt"
    "io/ioutil"
    "os"
    "strconv"
    "sync"
    "time"
)

var wg sync.WaitGroup
var workDone int

type Students struct {
    Students []Student `json:"students"`
}
type Student struct {
    Name       string  `json:"vardas"`
    Year       int     `json:"kursas"`
    Grade      float32 `json:"vidurkis"`
    encryption string
}

const file1 string = "IFF7.9_SarockaT_L1a_dat1.json"
const file2 string = "IFF7.9_SarockaT_L1a_dat2.json"
const file3 string = "IFF7.9_SarockaT_L1a_dat3.json"
const filetest string = "test.json"
var finished bool = false;

func main() {

    // 1. Nuskaito duomenuu faila i duomenu struktura
    var studentsArray = ReadFromJson(file2)

    size := len(studentsArray.Students)
    workingChannel := make(chan Student)
    dataChannel := make(chan Student)
    resultsChannel := make(chan Student)
    toMainThread := make(chan Student)

    fmt.Println(studentsArray)

    // 2.1 Paleidzia 2 darbines gijas:
    threadnumber := 2
    count := 0
    for count < threadnumber  {
        go Worker(workingChannel,resultsChannel)

        count++
    }
    //go Worker(workingChannel,resultsChannel)
    //go Worker(workingChannel,resultsChannel)
    //go Worker(workingChannel,resultsChannel)

    // 2.2 Paleidzia viena duomenu masyva valdancia gija
    go AddDataToWorkingChannels(dataChannel, workingChannel, size)

    // 2.3 Paleidzia viena rezultatu masyva valdancia gija
    go ResultsControl(resultsChannel, toMainThread)

    // 3. Duomenu masyva valdanciai gijai po viena persiuncia visus nuskaitytus elementus is failo
    for _, item := range studentsArray.Students {
        dataChannel <- item
    }

    // 4. Is rezultatu masyva valdancios gijos gauna rezultatus.
    var resultArray []Student

    //counter:=0
    for{
        msg, open := <- toMainThread
        if !open{
            break
        }
        resultArray = append(resultArray, msg)
    }

    Sort(resultArray)
    /*
Loop:
    for{
        select{
        case result := <-toMainThread:{
            resultArray = append(resultArray, result)
            fmt.Println(result)
        }
        case <-time.After(2 * time.Second):{
            fmt.Println("DONE")
            break Loop
        }
        }
    }

     */

    // 5. Gautus rezultatus isveda i tekstini faila lentele.
    file, e := os.OpenFile("rez2.txt", os.O_CREATE | os.O_WRONLY, 0666)
    if e!= nil{
        fmt.Println(e)
    }else{
        fmt.Fprintf(file, "%-10s %-10s %-10s \r\n", "Name", "Year", "Grade")
        fmt.Fprintf(file,"--------------------------------------------- \r\n")
        for _, item := range resultArray{
            fmt.Fprintf(file, "%-10s %-10s %-10s \r\n", item.Name, strconv.Itoa(item.Year), strconv.FormatFloat(float64(item.Grade), 'f', -1, 32))
            //file.WriteString(toString(item) + "    " + "\r\n")

        }
    }
    file.Close()

}

func Sort( resultArray []Student) {

    l := len(resultArray)
    for i := 1; i < l; i++ {
        j := i
        for j > 0 && resultArray[j].Name < resultArray[j-1].Name {
            resultArray[j], resultArray[j-1] = resultArray[j-1], resultArray[j]
            j -= 1
        }
    }
}

func toString(student Student)(stringed string){
    stringed+= student.Name+" ";
    stringed+= strconv.Itoa(student.Year)+" "
    stringed+= strconv.FormatFloat(float64(student.Grade), 'f', -1, 32)
    return
}

// ReadFromJson
func ReadFromJson(path string) Students {
    jsonFile, err := os.Open(path)
    if err != nil {
        fmt.Println(err)
    }
    defer jsonFile.Close()
    byteValue, _ := ioutil.ReadAll(jsonFile)
    var studentArray Students
    json.Unmarshal(byteValue, &studentArray)
    return studentArray
}
// created function where data goes from dataChannel to workingChannel
func AddDataToWorkingChannels(dataChannel <-chan Student, workingChannel chan<- Student, size int) {
    studentsArray := make([]Student, (size / 5)) // lokalus masyvas, dydis < n/2
    var index int = -1
    count := 0
    for count<=size*2{
        var student Student
        if index==-1{ // Jei tuscias
            student = <- dataChannel
            index++
            studentsArray[index] = student
            count++
        }else if index==(size/5)-1{ // Jei pilnas
            workingChannel <- studentsArray[index]
            index--
            count++
        }else {
            select {
            case student = <-dataChannel:
                {
                    index++
                    studentsArray[index] = student;
                    count++
                }
            case workingChannel <- studentsArray[index]:
                {
                    index--
                    count++
                }
            }
        }
        if count >= size*2{
            break
        }
    }
    close(workingChannel)
}
func Worker(workingChannel <-chan Student, resultsChannel chan<- Student) {

    for{
        msg, open := <- workingChannel
        if !open{
            //fmt.Println("GNAGNGANAGNGANAGNAGNAGNAGN111111111111111")
            break
        }

        if msg.Grade <= 5{ // B raide
            continue
        }
        //fmt.Println(msg.Grade)
        resultsChannel <- msg

    }

    //close(resultsChannel)
    /*
    for{
        select {
        case player := <-workingChannel:{

            if player.Grade <= 5{
                continue
            }
            resultsChannel <- player
            //fmt.Println(toString(player))
            //fmt.Println("Students name: "+player.Name)
            //fmt.Println("Student's year:  " + strconv.Itoa(player.Year))
            //fmt.Println("Student's grade: " + strconv.FormatFloat(float64(player.Grade), 'f', -1, 32))
        }
        }
    }
     */
}
func ResultsControl(resultsChannel <-chan Student, toMainThread chan<- Student){
    var resultArr []Student

    count:=0
Loop:
    for{
        select{
        case result := <-resultsChannel:{
            resultArr = append(resultArr, result)
            count++
        }
        case <-time.After(1 * time.Second):{
            fmt.Println(strconv.Itoa(count))
            break Loop
        }
        }
    }

    /*
            for i:=0; i<count; i++{
            result := <-resultsChannel
            resultArr = append(resultArr, result)
        }
    */
    for _, item := range resultArr{
        toMainThread <- item
    }
    close(toMainThread)
    //fmt.Println("BROKEN")
}

// prints all players
func PrintPlayersToConsole(carsArray Students) {
    for i := 0; i < len(carsArray.Students); i++ {
        fmt.Println("Student's name: " + carsArray.Students[i].Name)
        fmt.Println("Student's year:  " + strconv.Itoa(carsArray.Students[i].Year))
        fmt.Println("Student's price: " + strconv.FormatFloat(float64(carsArray.Students[i].Grade), 'f', -1, 32))
    }
}








------------------------------------------------------------------------------------------------------------------

{
    "students": [
  {
    "vardas": "Jurgis",
    "kursas": 1,
    "vidurkis": 2.5
  },
  {
    "vardas": "Tobis",
    "kursas": 2,
    "vidurkis": 7.0
  },
  {
    "vardas": "Tautvydas",
    "kursas": 4,
    "vidurkis": 1.01
  },
  {
    "vardas": "Samanta",
    "kursas": 3,
    "vidurkis": 0.13
  },
  {
    "vardas": "Antanas",
    "kursas": 1,
    "vidurkis": 0.95
  },
  {
    "vardas": "Kazys",
    "kursas": 2,
    "vidurkis": 8.65
  },
  {
    "vardas": "Petras",
    "kursas": 2,
    "vidurkis": 7.01
  },
  {
    "vardas": "Sonata",
    "kursas": 3,
    "vidurkis": 9.13
  },

  {
    "vardas": "Jonas",
    "kursas": 1,
    "vidurkis": 2.95
  },
  {
    "vardas": "Martynas",
    "kursas": 3,
    "vidurkis": 9.13
  },
  {
    "vardas": "Arturas",
    "kursas": 2,
    "vidurkis": 7.01
  },
  {
    "vardas": "Vacys",
    "kursas": 2,
    "vidurkis": 8.65
  },
  {
    "vardas": "Robertas",
    "kursas": 3,
    "vidurkis": 2.43
  },
  {
    "vardas": "Mykolas",
    "kursas": 1,
    "vidurkis": 6.95
  },
  {
    "vardas": "Aldona",
    "kursas": 3,
    "vidurkis": 9.13
  },
  {
    "vardas": "Asta",
    "kursas": 2,
    "vidurkis": 7.01
  },
  {
    "vardas": "Viktoras",
    "kursas": 2,
    "vidurkis": 2.65
  },
  {
    "vardas": "Artuturas",
    "kursas": 5,
    "vidurkis": 8.32
  },
  {
    "vardas": "Vytas",
    "kursas": 3,
    "vidurkis": 7.85
  },
  {
    "vardas": "Jonas",
    "kursas": 1,
    "vidurkis": 6.95
  },
  {
    "vardas": "Zigmas",
    "kursas": 3,
    "vidurkis": 2.13
  },
  {
    "vardas": "Artturas",
    "kursas": 2,
    "vidurkis": 7.01
  },
  {
    "vardas": "Simas",
    "kursas": 3,
    "vidurkis": 6.43
  },
  {
    "vardas": "Diana",
    "kursas": 2,
    "vidurkis": 4.01
  },
  {
    "vardas": "Liucija",
    "kursas": 3,
    "vidurkis": 5.01
  }
]
}